Hi,
It may be easier and possibly cheaper to replace the [https://www.ebay.com/itm/153767863406|keyboard] (supplier example only) rather than trying to fix or [https://laptopkey.com/asus-q-series-q405u-laptop-keyboard-key-replacement/|replace the individual keys] (supplier example only).
In trying to fix it you may create more problems than what you originally had. If you suspect that liquid damage was responsible then perhaps more keys will also fail soon.
Here’s a [https://www.youtube.com/watch?v=y-aBr-rL2f0|video] that shows how to remove the upper case/keyboard assembly that may help if you decide to replace the keyboard